| xf.li | bdd93d5 | 2023-05-12 07:10:14 -0700 | [diff] [blame] | 1 | /* Determine the length of a string. For Intel 80x86, x>=3. |
| 2 | Copyright (C) 1991-2016 Free Software Foundation, Inc. |
| 3 | This file is part of the GNU C Library. |
| 4 | Contributed by Torbjorn Granlund (tege@sics.se). |
| 5 | |
| 6 | The GNU C Library is free software; you can redistribute it and/or |
| 7 | modify it under the terms of the GNU Lesser General Public |
| 8 | License as published by the Free Software Foundation; either |
| 9 | version 2.1 of the License, or (at your option) any later version. |
| 10 | |
| 11 | The GNU C Library is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | Lesser General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU Lesser General Public |
| 17 | License along with the GNU C Library; if not, see |
| 18 | <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include <string.h> |
| 21 | |
| 22 | size_t |
| 23 | strlen (const char *str) |
| 24 | { |
| 25 | int cnt; |
| 26 | |
| 27 | asm("cld\n" /* Search forward. */ |
| 28 | /* Some old versions of gas need `repne' instead of `repnz'. */ |
| 29 | "repnz\n" /* Look for a zero byte. */ |
| 30 | "scasb" /* %0, %1, %3 */ : |
| 31 | "=c" (cnt) : "D" (str), "0" (-1), "a" (0)); |
| 32 | |
| 33 | return -2 - cnt; |
| 34 | } |
| 35 | libc_hidden_builtin_def (strlen) |